Impact of directed energy deposition parameters on mechanical distortion of laser deposited Ti-6Al-4V

The effects of laser-based powder-fed directed energy deposition processing parameters on the distortion of deposited Ti-6Al-4V parts are assessed through in situ monitoring. Experiments were conducted wherein substrate thickness, deposition thickness, and initial substrate temperature were varied in order to investigate their effects on distortion. Correlations of process parameters to the mechanical characteristic were also developed, uncovering some of the driving mechanisms of the measured characteristic. This work highlights the impact of substrate preheating on distortion. Most notably, the effect of initial substrate temperature on distortion depended on the size of the substrate. On thin substrates, preheating reduced the total amount of distortion. However on thick substrates, preheating increased the amount of distortion. Techniques to mitigate the unwanted mechanical defect are discussed.